Efficient Nitrate Synthesis via Ambient Nitrogen Oxidation with Ru-Doped TiO2/RuO2 Electrocatalysts.

Author(s) Kuang, M.; Wang, Y.; Fang, W.; Tan, H.; Chen, M.; Yao, J.; Liu, C.; Xu, J.; Zhou, K.; Yan, Q.
Journal Adv Mater
Date Published 2020 May 25

A facile pathway of the electrocatalytic nitrogen oxidation reaction (NOR) to nitrate is proposed, and Ru-doped TiO /RuO (abbreviated as Ru/TiO ) as a proof-of-concept catalyst is employed accordingly. Density functional theory (DFT) calculations suggest that Ru can function as the main active center for the NOR process. Remarkably doping Ru into the TiO lattice can induce an upshift of the d-band center of the Ru site, resulting in enhanced activity for accelerating electrochemical conversion of inert N to active NO*. Overdoping of Ru ions will lead to the formation of additional RuO on the TiO surface, which provides oxygen evolution reaction (OER) active sites for promoting the redox transformation of the NO* intermediate to nitrate. However, too much RuO in the catalyst is detrimental to both the selectivity of the NOR and the Faradaic efficiency due to the dominant OER process. Experimentally, a considerable nitrate yield rate of 161.9 µmol h g (besides, a total nitrate yield of 47.9 µg during 50 h) and a highest nitrate Faradaic efficiency of 26.1% are achieved by the Ru/TiO catalyst (with the hybrid composition of Ru Ti O and extra RuO by 2.79 wt% Ru addition amount) in 0.1 m Na SO electrolyte.

DOI 10.1002/adma.202002189
ISSN 1521-4095
Citation Adv Mater Weinheim. 2020:e2002189.

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